• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.541-548
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• 2005

The research deals with the prediction and the measurement of electromagnetic wave propagation in rectangular shaped tunnels at f=2.65 GHz. The received power level was measured in the straight and the curved tunnel by using a spectrum analyzer and Satellite DMB mobile phone. Thus we have gotten the data for two cases, the straight and the curved tunnel whose radius is 300m. In addition, the prediction of wave propagation was conducted based on the ray-launching method, in same tunnel where measurement was performed. A good agreement of the measured and the predicted path loss could be confirmed. The measured path loss shows a marked difference in propagation loss: the path-loss exponent, 3.21, and 3.98, for a straight and a curved tunnel, respectively. The reason that path-loss exponent is high in a curved tunnel is that there is no direct wave but only the reflected waves, which attenuates rapidly with distance due to multiple reflections. Also the predicted path loss shows path loss exeponent, 3.2 and 3.95, for a straight and a curved tunnel which are similar to the simulation results.

• The KIPS Transactions:PartB
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• v.12B no.6 s.102
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• pp.637-646
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• 2005

Most of the multimedia contents for DBM services art provided as MPEG-2 bit streams. However, they have to be transcoded to H.264 bit streams for practical services because the standard video codec for DMB is H.264. The existing transcoder architecture is Cascaded Pixel-Domain Transcoding Architecture, which consists of the MPEG-2 dacoding phase and the H.264 encoding phase. This architecture can be easily implemented using MPEG-2 decoder and H.264 encoder without source modifying. However. It has disadvantages in transcoding time and DCT-mismatch problem. In this paper, we propose two kinds of transcoder architecture, DCT-OPEN and DCT-CLOSED, to complement the CPDT architecture. Although DCT-OPEN has lower PSNR than CPDT due to drift problem, it is efficient for real-time transcoding. On the contrary, the DCT-CLOSED architecture has the advantage of PSNR over CPDT at the cost of transcoding time.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.75-82
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• 2010

This paper presents a wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer for a multi-band single chip CMOS RFIC transceivers. A wideband VCO utilizes a 6-bit switched capacitor array bank for 2340~3940 MHz frequency range. VCO frequency calibration circuit is designed for optimal capacitor bank code selection before phase locking process. It finishes the calibration process in $2{\mu}s$ over the whole frequency band. The LO generation block has selectable multiple division ratios of ${\div}2$, ${\div}16$, and ${\div}32$ to generate LO I/Q signals for T-DMB/DAB/FM Radio systems in L-Band (1173~1973 MHz), VHF-III (147~246 MHz), VFH-II (74~123 MHz), respectively. The measured integrated phase noise is quite low as it is lower than 0.8 degree RMS over the whole frequency band. Total locking time of the ${\Delta}{\Sigma}$ frequency synthesizer including VCO frequency calibration time is less than $50{\mu}s$. The wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer is fabricated in $0.13{\mu}m$ CMOS technology, and it consumes 15.8 mA from 1.2 V DC supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1343-1351
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• 2010

In this paper, a novel patch antenna based on the metamaterial CRLH(Composite Right- and Left-Handed) structure is designed, implemented, and measured. Contrary to the standard microstrip patch's fundamental resonance mode of half-wavelength or its positive multiple, the proposed antenna shows the in-phase electric field over the entire antenna. The proposed antenna has a desired omni-directional field pattern which is typical characteristic of $\lambda/4$ monopole antenna, and also shows the merit of low profile. HFSS(High Frequency Structure Simulator) of Ansoft which is based on the FEM(Finite Element Method) is used to simulate the proposed antenna. FR-4 substrate of thickness 1.6 mm and relative permitivity 4.4 is used for the proposed antenna implementation. The implemented antenna showed VSWR (Voltage Standarding Wave Ratio)$\leq$2 for the frequency band from 2.63 GHz to 2.655 GHz which is used for S-DMB (Satellite-Digital Multimedia Broadcasting) service. And measured peak gain and efficiency are 2.65 dBi and 81.14 %, respectively.

• 정보화사회
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• s.174
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• pp.16-17
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• 2005

휴대전화로 방송을 보고 TV로 인터넷을 하는 등 통신과 방송의 융합이 가속화되고 있다. 이동 중에도 방송을 볼 수 있는 위성DMB가 이미 정식 서비스를 시작했고, 인터넷 방송으로 불리는 IPTV도 올해 안에 모습을 드러낼 예정이다. 위성방송 스카이라이프는 얼마 전 'TV 주문 서비스'를 시작했다. 가입자가 리모콘으로 피자의 종류와 가격 등을 검색해 주문하면 거주지에서 가장 가까운 지점에서 배달해 준다. 통신과 방송의 융합 시대가 본격적으로 열리고 있는 것이다.

• Digital Contents
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• no.7 s.146
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• pp.99-99
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• 2005

한국 · 호주 · 뉴질랜드 3국의 IT분야 정부 및 기업 대표들이 한자리에 모였다. 정보통신부는 지난달 9월10일 서울 신라호텔에서‘한국 · 호주 · 뉴질랜드 브로드밴드 서밋 2005’행사를 개최했다. 총 5개의 세션으로 진행된 이번 행사에서는 3국 정부 대표가 자국의 주요 IT정책을 발표하고 DMB∙홈네트워크 · 브로드밴드 네트워크 등 에 대한 협력방안을 논의했다.

• Digital Contents
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• no.4 s.155
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• pp.88-89
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• 2006

지난 1월 문화관광부는 국내 애니메이션 산업 발전을 위한 '애니메이션 산업 중장기 발전 전략'을 발표했다. 핵심은 오는 2010년까지 애니메이션 매출 1조원을 달성한다는 것, 국내 애니메이션 업계는 애니메이션 총량제 시행과 DMB등 신규 매체의 보급 등으로 인해 새로운 성장 기회를 맞이하고 있으며 그 어느 때보다 창작 애니메이션에 대한 요구가 높아지고 있는 상황이다. 이에 따라 수준 높은 애니메이션 창작을 유도하기 위한 판정지침도 이를 뒷받침할 수 있는 방향으로 개선돼야 할 필요성이 대두되고 있다.

• Digital Contents
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• no.4 s.155
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• pp.68-73
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• 2006

우리네 일상에서 옷을 입고 밥을 먹고 잠을 자는 행위만큼이나 당연하고 자연스러운 일로 TV 시청을 든다면 대부분 수긍할 것이다. 물론 요즘 일부에서는 TV안보기 운동 등을 벌이며 TV의 존재감을 애서 무시하려고 하지만 , 그만큼 TV는 우리 생활 깊숙이 들어와 있다고 할 수 있다. 최근 들어 TV관련 이슈가 많이 나오고 있다 . 휴대가 간편한 DMB단말기에서부터 인터넷 망을 이용해 즐기는 IPTV에 이르기까지 이제 TV는 새로운 모습으로 시청자들에게 다가서고 있다.

• TTA Journal
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• s.107
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• pp.54-58
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• 2006

DMB로 대표되는 국내 이동형 TV가 이제는 인터넷과 어우러져 IPTV로 빠르게 진화하고 있다. 국내에서는 이미 관련 업체를 중심으로 많은 개발과 서비스가 개발되고 있는 상황에서 금년 초 ITU-T에서의 IPTV Focus Group의 활동은 그 움직임을 더욱 가속화 시켰다. 본 기고문에서는 현재의 연구 중심인 고정형 IPTV 최근 현황과 이와 관련된 다양한 기술적 이슈를 동시에 살펴본다.